Coastal aquifers are valuable resources of fresh water for domestic and industrial use. However, over-abstraction leaves them at risk of contamination by saltwater, which migrates into the aquifer in response to abstraction. Detecting and monitoring the movement of saltwater is difficult, as the methods currently available rely on data acquired at production or monitoring wells. Consequently, it is typically of low spatial resolution. Moreover, once saltwater reaches the production well(s), it is too late to take action; that region of the aquifer has already been contaminated. This problem is exacerbated in chalk aquifers owing to their dual porosity behaviour and high transmissivity. The aim of this project is to develop new technology, based on measurements of electrical potential (the so-called spontaneous- or self-potential), to detect and monitor the movement of saltwater during freshwater abstraction. The electrical potential is measured using electrodes installed at the earth surface and/or in production or monitoring wells. The advantage of the technique is that saline fronts may be monitored while they are several tens to hundreds of metres away from the monitoring location. Consequently, saline water moving into an aquifer may be detected before it reaches the abstraction well(s), allowing abstraction to be managed proactively so as to avoid widespread contamination of the aquifer. The innovative, multidisciplinary project builds on existing work undertaken at Imperial College, in which measurements of the spontaneous potential, acquired from electrodes permanently installed downhole, are used to monitor water movement in oil or gas reservoirs during production. The underlying rationale in hydrocarbon applications is similar, in that waterfronts may be monitored while they are several tens to hundreds of metres away from the production well, allowing production to be managed proactively so as to avoid excessive unwanted water. This is contaminated and so expensive to treat and dispose of. The project will provide new experimental data, which is required to model and interpret measurements of spontaneous potential in coastal chalk aquifers. The project will also use numerical modeling to determine whether the saline front can be detected and monitored, and over what distances and at what spatial and temporal resolution. Finally, the utility of the method will be demonstrated at a well-characterized chalk aquifer test site, via field experiments in which small volumes of saline water are injected and the resulting electrical signals are measured. This is an essential step to establish credibility prior to deployment in a commercial abstraction project. The results will be of direct benefit to UK plc, because they contribute to the sustainable management of water resources, helping to preserve and maintain these as demand continues to increase. See the attached document 'Case for Support' for further details of the scientific case, aims and objectives, and scope of work.

Water pollution, in the form of nutrient enrichment and algal blooms, causes water quality problems across the globe, resulting in health risks and large costs to water managers and regulators tasked with ensuring clean water supply and healthy rivers, lakes and reservoirs. Monitoring of water chemistry is essential for complying with relevant regulations and maintaining water security. Nutrient chemistry is typically measured by manual sampling and later laboratory analysis. The laborious, discrete, non-real-time nature of this method means that pollution events cannot be suitably characterised in a timely manner or can sometimes be missed completely. Low frequency and single nutrient measurement also currently limits our ability to understand processes or forecast future conditions accurately. The challenge the project addresses: Recent innovations and the development of high-frequency nutrient auto-analysers have the potential to transform our understanding of nutrient/pollutant sources and dynamics. This move to near real-time data provides the opportunity to significantly improve how catchments are managed and resources are protected. They are therefore of great potential interest to water companies and regulators, as evidence of meeting water quality targets and identifying pollutant sources. However, state-of-the-art commercial nutrient auto-analyser instruments are expensive to purchase (e.g. £20-35K per device), and expensive to run with high reagent costs and service contracts, they can be unreliable. In addition, conventionally, individual nutrients are monitored by different devices, resulting in prohibitively high costs for multiple separate nutrient systems. This is a critical barrier to the widespread adoption of nutrient monitoring sensors in freshwaters.

The world's population likes living by the sea. Currently approximately 53% of us live on the 10% of the earth's surface that is within 200km of the coast; this is forecast to rise to 75% by 2050. This increased concentration of people in restricted areas will place greater stress on natural resources including water supplies. These resources must be used in a judicious manner if we are to live within our means. Meeting the needs for providing potable water to 75% of humanity from such a limited resource forms a major global challenge facing society in the 21st Century. Groundwater has been recognised for some time for its capacity to provide good quality water, particularity in places where other water sources have either poor quality, requiring expensive (and environmentally unfriendly) treatment technologies, or are unavailable. However, it needs to be used cautiously. Over-pumping of coastal aquifers can lead to seawater contaminating groundwater supplies, thereby destroying otherwise valuable resources. Contamination by even 1% salt water can be enough to render freshwater unfit for use. This issue is of concern in the UK, where saline intrusion (SI) can affect the quality of water used for human consumption, as well as for industrial purposes (process water and irrigation). Further afield, this matter is of pressing concern across Europe, particularly in Mediterranean countries, as well as in other water-stressed arid and semi-arid regions of the planet where use of desalinisation technologies may not be viable over the long term. The UK Water Research and Innovation Partnership has highlighted weaknesses in the UK water industry that could prevent it from maintaining its position against increasing external competition. In order to develop a 10% Global market share, worth $8.8 billion, the UK needs to invest in water research to maintain its competitive edge. The partnership has identified opportunities for developing innovative water technologies in 21 areas, where it believes that the UK can compete on the world stage. Developing these technologies requires a firm scientific underpinning. This proposal addresses developing expertise in the area of SI using accurate monitoring, prediction and control systems. Findings will underpin protocols that will increase the effectiveness of sustainable water infrastructure management through demand management tools. The proposal's multidisciplinary research team from Queen's University Belfast and Imperial College London brings together expertise in the areas of experimental hydrodynamics, process engineering, numerical simulation, computational fluid dynamics, field hydro-geology and geophysics; this is further strengthened through active involvement of the British Geological Survey. The integration of experimentation with testing and monitoring in real world environments, along with improved numerical simulation that will lead to the development of an early warning system for salt water breakthrough to provide a sustainable managed approach for water abstraction in coastal areas. Understanding the movement of seawater and freshwater within coastal aquifers, and the interactions that take place under naturally complex ground conditions, provides the key to unlocking suitable approaches for designing and maintaining effective water management systems needed to meet the ever growing demand for high quality freshwater in coastal areas. Our vision is to create a novel system capable of providing early warning of salt water intrusion within groundwater wells. This advance notification, of up to 8 days, will allow actions to be taken in advance of contamination occurring. A dynamic model, which will further help with the understanding of the transient processes that govern SI movement under real world conditions, will provide a novel practical management suite of tools for water suppliers and environmental regulators.

A reliable water supply is usually taken for granted in the UK. However, there is increasing pressure on water supplies. By 2050, anthropogenic climate change and increasing water demand from a growing population is projected to lead to frequent water shortages across the UK, with projections estimating more than 3 billion litres of additional water a day required to ensure supply. An extreme drought could exceed the coping capacity of many water companies leading to severe supply restrictions and costing up to £40 billion in emergency water supply measures alone. Predicting plausible 'worst case' droughts and their impacts on river flows is vital to test the resilience of current water supply systems, to support critical planning decisions such as future investment in supply infrastructure (e.g. reservoirs, desalination plants, inter-catchment water transfer schemes) and to ensure adequate future water supply for food-energy-water systems. This is a challenge as current understanding of how freshwater resources will respond to changes in water supply and water demand remain poorly understood and quantified, particularly for extreme drought events. The problem is two-fold. Firstly, the models we currently use to inform water resource decisions currently neglect key interactions between human water-use (such as reservoir storage, irrigation, hydro-power generation) and terrestrial water fluxes (such as hillslope runoff, surface water and groundwater flow). Secondly, such extreme drought events are especially difficult to characterise and predict. Droughts are complex phenomena that vary across multiple spatial and temporal scales from small river reaches to continental scales lasting for weeks to decades. This research addresses these challenges by establishing the resilience of water systems across Great Britain to extreme droughts. It will develop new integrated modelling tools and leverage unique datasets of human-water use to determine how freshwater resources (river flows and groundwater levels) will respond to changes in water supply (from anthropogenic climate change) and water demand (from human water use). The integrated modelling framework will explicitly characterise the interactions and feedbacks between human-water use (from domestic, agricultural and industrial demand) and hydro-climatic processes (land-atmosphere, hillslope runoff and surface-groundwater interactions). This will be used to facilitate a step-change in UK drought prediction and generate new understanding of how human-water interactions alleviate or enhance hydrological droughts that will feed into the next generation of earth system models. I will develop nationally consistent, open access libraries of meteorological and hydrological drought events to provide the first extreme drought projections for Great Britain that account for changes in future water supply and demand. These new datasets will be used to support critical decisions on how best to manage future water resources in collaboration with key project partners including water companies, regional planning groups, regulatory bodies and research institutes.

The quality of potable water is of vital importance to public health. However, contamination events are observed to occur even in the tiny volume (relative to total supply volume) of the samples collected for regulatory purposes. These events are often unexplained. A possible source of such contamination is pollutant ingress into the distribution system from the surrounding soil and water. Such ingress can occur through the many apertures normally associated with leakage, at times when low or negative pressure conditions occur such as due to hydraulic transients (water hammer).This project will investigate the currently unknown potential for such contaminant ingress into potable water distribution systems by direct measurement utilising a specially developed laboratory facility. Laboratory studies are necessary to address difficulties associated with the short response duration of transient events and the costs, complexity and regulatory unacceptability of field studies. The experimental set up will be full scale and include surrounding ground conditions and a contaminant flow field (for example, an adjacent leaky sewer). Initial studies will investigate the influence of the characteristics of the transients (magnitude, duration etc.) while further studies will investigate the influence of aperture shape, geometry and location.The experiments will provide quantitative evidence of the conditions causing ingress which will be used to develop a new ingress model which, together with existing modelling tools, will enable quantification of the potential for contaminant ingress. The outputs from the new modelling approach will inform improvements to distribution system design, operation and maintenance, management of pollution incidents and ultimately result in improved drinking water quality.The project will be undertaken at the University of Sheffield, with advice and support from Professor Bryan Karney of Toronto University, an international expert in transient analysis and in collaboration with Ecole Polytechnique de Montreal for access to the best currently available relevant field data.